Nothing wrong with doing the whole written before doing the flying. The only drawback is you might be more excited with the stimulus of flying .If you get the written done, the flying will be easy and fun.You don't have to do it all first though,you can lead with the ground school and go along with the flying also.
Some guys make the mistake of doing all the flying and get way behind on the written, or they slop off on the written stuff. It is not that hard, some of it is pretty interesting and there is no reason not to make in the 90s. Whatever you miss may be what the oral part of the PPL flight test will emphasize. It is not hard to learn it the first time, they give you ALL the questions verbatim, you just have to cover them.
I am not sure about the Cessna course, it is likely good. Is it from King?
The best course is the top King one. I think it it about $295. It not only has books, but the real KEY thing is the INTERACTIIVE computer disk. You do the lesson on your computer, you study, take the practice questions right there, it is graded right then and there and you get the explantions and correct answers to any you missed right there. A great time saver, and keeps your interest,and will save money in the long run.
King has also regular video courses as does Sporty's, about $200. I think the interactive part is well worth the money and I am nto a computer geek.
I think a sharp and dedicated person could do the ground school course in a few weeks if they put in perhaps 3 to 4 hours a day. You can probably do about one section or chapter in a day or two.
There will be a video or book on what to know BEFORE you go in the airplane to try a procedure. It is vital to know most of this before you get in the plane, to save a lot of money. You don't want to be paying a CFI and for a rental plane time, perhaps $90, just to explain something you could have learned most of at home for free. An example is practicing stalls and recovery. You can learn the cause of a stall ,( too much angle of attack makes not enough wind over the wings to lift), the warning signs (horn, sloppy controls, buffet etc.), and recovery ( release back pressure)., before you pay a penny for CFI or plane. Some CFIs are real concientious to teach you before each flight, but the school and the CFI make there money when that engine is running, so they are motivated that way.
The Machado book seem ok, the red Gleim ones, or Jepp are good too. I thnk either video course is easier and faster than any book alone. If money is real tight, you might see if a past student has a course to sell you or if there is one at the libraby.
Just get started, go do it. If you are serious and want to call me to talk about this, some evening, I am in 411 info. Bill Greenwood , Aspen, Co.